Internal-combustion heater



March 18, H. J. DE N. Mcco LuM mmmmi counus-rron nsu'nn Filed Aug. 3, 1942 4 Sheets-Shut 1 N) 9%! @Zlemw f Ma/M March 18, 1947. H. JJbE N. M coLLuM ,50

INTERNAL cousu s'rxog aum:

Filed Aug. 5, 194 2 4 Sheets-S1190: 2

- ilaqrnngq March 18, 1947. H. J, D: N, McCOLLUM 2,417,603

' INTERNAL c'oua us nou HEATER I Filed Aug. 3. 1942 v 4 Sheets-Sheet 3 azmzzmq, @Zlcuna March 18, 194-7.; P NMCCQLLUM 2,417,603

xmmmomsmu HEATER Filed Aug. 3, 1942 4 Sheets-Sheet 4 26 c3; nae/razor ii g Patented Mar. 18, 1947 INTERNAL-COMBUSTION HEATER- Henry J. De N. McCollum, Chicago, Ill.; Thelma McCollum, executrix of said Henry J. De N.

McCollum,

deceased, assignor to Stewart- Warner Corporation, Chicago, 111., a corporation of Virginia Application August 3, 1942, Serial No. 453,348 Claims. (01. 158-28) My invention pertains to heaters and is more particularly concerned with a unitary, internal combustion heater of a type which can be utilized to heat the cabin or other space of an airplane or for heating the passenger compartments of other vehicles, or for other similar purposes.

An object of my invention is to provide a unitary, internal combustion heater which is compact and of light weight construction so that it is ideally suited for use in aircraft and for similar purposes where weight and space are particularly important. v

Another object of my invention is to provide an internal combustion heater which can be readily attached to any suitable support and which will provide a maximum'of heat with a minimum of servicing and other attention.

Another object of my invention is to provide an internal combustion heater which can be operated by a person having no particular familiarity with the construction of the heater or any special mechanical or technical training.

Another object of my invention is to provide an internal combustion heater which is highly eiiicient and which consumes a small amount of fuel for the heat produced.

Another object of my invention is to provide an internal combustion heater which is quiet and free from vibration.

Another object of my invention is to provide an internal combustion heater which can be readily manufactured in large quantities by conventional equipment and methods.

Other objects and advantages will become apparent as the description proceeds.

In thedrawings: V v

Fig. 1 is a side elevation of a heater embodying a preferred form of my invention;

Fig. 2 is a top plan view of the heater shown in Fig. l with a part of the fan cut away to show more clearly structure located therebeneath;

Fig. 3 is an end elevation lookingin the direction of the arrow 3 in Fig. 1; I

Fig. 4 is a vertical section taken on the line 4--4 of Fig. 2; and

Fig. 5 is a view of the blower with part of the casing cut away to show the manner in which the impeller is mounted on its driving shaft.

The heater illustrated in the drawings is a self-contained, internal combustion heater having a frame Ill-provided with grommets H for receiving bolts or other suitable attaching means and so distributed about the frame I0 that either side of the heater may be attached to a wall or other suitable support. After the heater has been suitably installed by attaching it to a wall or other support, the electrical circuits of the heater are connected with a battery or other suitable source of electrical current and the nipple II, which constitutes the gasoline inlet, is connected to a pipe leading from a gasoline tank or other suitable source of fuel supply.

Admission of gasoline through the inlet I4 is controlledby a solenoid valve I6 located between the inlet I4 and pipe l8 leading to carburetor 20. The air for the carburetor 20 is supplied to the carburetor through a pipe 22 connected to the outlet of a blower 24, having an impeller 26 mounted on a shaft 28 driven by a motor (not shown) located in a motor housing 30. The motor housing 30 is interposed between the blower 24 and an air cleaner 32 through which the air for the blower is drawn by the suction created in the blower. The air cleaner 32 has a bracket 34 provided with a strap 36 which encircles the motor housing, as best shown in Fig. 2, and secures the air cleaner to the lower end of this housing, as viewed in this figure.

Air drawn in through the air cleaner 32 passes through the motor and housing 30 and cools the blower motor located therein. This air then passes to the blower 24 and is discharged through pipe 22 to carburetor 20, where it mixes with the \gasoline to form a combustible mixture. The pipe 22 is provided with a throttle valve 38, which is urged toward closed position by a spring 40. This valve may be opened to any desired extent by the wire or operating rod 42 (Fig. l) which is connected to any suitable manual or automatic control. The wire or rod 42 is illustrated in Fig. 1 as being guided by a clip 44 attached to the carburetor 20.

The combustible mixture formed by the carburetor 20 passes through a connection 46, which, preferably, includes a flame arrester to the burner inlet 48. The .burner is provided with an electrical igniter for initially igniting the combustible mixture introduced through the burner inlet 48. It will be understood by those skilled in the art that after the 'burner has attained normal operation conditions, the igniter 50 is preferably disconnected-from its source of electrical supply and a re-igniter or other suitable means is pro vided to relight the mixture should the flame be extinguished because of'a temporary interruption in the mixture supply after the igniter has been deenergized.

The hot products of combustion flow between the perforated inner casing wall 52 of a muiller 54. filled with glass wool 56 or other suitable acoustic vibration absorbing material, and the wall 88 provided with external fins 68. The wall 52 is also provided with ribs or fins 82, which project radially outwardly into the annular space formed between the walls 52 and 58 and facilitate the transfer of heat from the hot gases flowing in the passageways formed by these walls and the ribs to the wall 58 and fins 88. f

After the hot gases have passed between the walls 52 and 58 and have given up most of their heat, they flow into an annular chamber 84, communicating with the Venturi-like throat 88 forming a restricted outlet to a discharge pipe 88. When the heater is located in the cabin of an airplane, the pipe 88 would lead to the exterior of the cabin and would discharge to atmosphere, the outlet end of the pipe 68 being so arranged thatmovement of the plane would not interfere with the discharge of the exhaust gases from this pipe and usually the outlet end of this pipe 68 would be pointed toward the rear of the plane so that movement of the plane would facilitate discharge of the exhaust gases from the heater. The exhaust pipe 88 is formed as part of the casing of blower 24 so that the latter is heated by the exhaust gases and the air supplied by the blower preheated to an extent sufficient to prevent icing of the carburetor, and also, due to improved vaporization of the fuel, increasing the efficiency of operation of the heater at high altitudes.

In order to increase the efliciency of the heater and reduce its weight, I make the parts of the heater of light-weight material and as thin as possible, and provide special means to protect these parts against explosive forces. I accomplish this by diluting the gases exhausted from the heater with air to such an extent that the resulting mixture is non-explosive and non-combustible even where the combustible mixture supplied to the heater by the carburetor has passed through the heater without being ignited. In this manner, explosions of gases which were not burned in the heater, are absolutely prevented, and it is, therefore, unnecessary to make the heater parts strong enough to withstand such explosions.

In Fig. 1, I have shown the blower 24 as being provided with a T connection 18, through which part of the air delivered by the blower is discharged. One side of the T connection I8 is connected by pipe 12 to the space 84, which receives gases which have passed through the heater. The air admitted to the space 84 through pipe 12 mixes with the gas flowing into this space from the heater and the resulting mixture is discharged through throat 68 and exhaust pipe 68. Throat 68 serves to maintain a pressure in the heater slightly above atmospheric and thus increases the operating efilciency of the heater.

The upper end of the frame l8 has inwardly directed arms 14 forming a support for a fan I6 comprising an electric motor 18 and fan blades 88 driven by this motor. Except for the presence of the motor 18, the upper end of the frame I8 is open and the blades 88 draw air through this open ended frame and discharge it downwardly over the heater fins 88 and 82. The frame I8 is provided with a casing or sleeve-like extension 84 surrounding the'fins 88 and 82 and insuring that air discharged by the fan It will flow in intimate contact with these fins and pick up heat therefrom. The lower end of the casing 84 is open and the heated air is discharged through this opening to the airplane cabin or other space '10 open position. From an examination of Fig. 5,

it will be apparent that the blower 24 has a housing 88 provided with a removable cover 88, of such size that when the cover is removed the impeller-28 may be inserted or removed. The

impeller 28 is secured to -its driving shaft 28,

which is an extension of the armature shaft of the motor, by set screws 82, and the construction is such that after the heater has otherwise been completely assembled, impeller 26 may be attached to its shaft and cover 88 then secured in place. Thisdelayed installation of the impelier makes it possible to locate the impeller on its shaft so as to allow for unavoidable slight variations in the dimensions of the motor and blower parts, which would affect the positioning of the shaft 28 relative to the impeller housing 88 and cover 88.

It will be understood that my heater is adapted to incorporate any of the usual electrical con- 30 trols provided for internal combustion heaters of this general type. In Fig. 1 I have shown a junction box 94 as providing a suitable arrangement for grouping the various electrical connections. Wires entering or leaving the junction 5 box 84 are preferably located in pipes 86 or protective conduits 98 for maximum safety, although any other suitable electrical wiring arrangement may be adopted in lieu of the particular arrangement shown.

40 From the foregoing description it will be seen that I have provided a novel heater of the unit type for burnin a liquid fuel, such as gasoline, supplied from a suitable fuel tank located at a distance from the heater and at a slightly lower level. The heater provides the pressure necessary to move the fuel from the tank to the heater so that no separate pump is required. Since the tank may be located at a lower level than the heater, there will be no danger of fuel flow into the heater when it is not in operation, even though the solenoid valve l8 should not seat perfectly. The heater can be readily attached to any suitable wall or other support and is ready for insant use after a minimum of connections has been 55 established.

In operation, the heater may be controlled by any suitable thermostatic switch or may be manually controlled. Upon electrically energizing the unit, the solenoid valve will be opened, and the 50 motor 38 and electrical ignition means will be energized. Ihe centrifugal blower will supply air under pressure to the fuel tank and fuel will flow through the open solenoid valve- IE to the carburetor 28, where it will be mixed with air supplied by the blower 24, and the mixture supplied to the combustion chamber of the heater where it will be ignited by the electrical igniter 58. At the same time, the blower will supply air under pressure through the tube 12 to the annular space 84 at the exhaust end of the heat exchanger. As

previously pointed out, this air will dilute the mixture sufiiciently that it will no longer be coml ustible as it flows through the exhaust conduit 76 Thus, when the igniter ignites the mixture in the combustion chamber, the explosive flame cannot possibly propagate itself beyond the discharge nozzle 66, since the mixture in the discharge conduit 68 and in any exhaust pipe connected to this conduit will be too dilute to burn. The exhaust conduit is therefore never subjected to the increased pressure and temperature which would result if a combustible mixture were permitted to flow into it and burn therein.

The gaseous products of combustion will, however, despite their dilution, contain a considerable amount of heat, and some of this heat will be transmitted to the casing of the blower 24, since the discharge pipe 68 is cast integrally with the casing 88. The resultingpreheating of the air supplied to the carburetor has the previously mentioned important advantages of preventing icing of the carburetor and improving combustion. The latter advantages are of particular importance when the heating unit is used for the heating of an airplane flying at high altitudes where the temperature may be of the order of 40 F. or 50 F., and the pressure may be very low. At these low pressures and temperatures, it is difficult to maintain combustion, even of such highly combustible fuels as aviation gasoine.

The preheating of the air supplied to the carburetor is, therefore, of considerable advantage,

and the fact that the blower acts as a supercharger to increase the pressure within the combustion chamber is likewise of importance in securing uninterrupted satisfactory heat output from the heater.

Because of its compactness and light weight, my heater is particularly adapted for use in airplanes, but it is also equally suitable for numerous other uses where a small, compact, inexpensive, unitary heater is desired. The novel construction provides a very compact and simple assembly with short pipe connections between-the various elements thereof.

While I have illustrated and described a single embodiment of my invention, my invention is not limited to the details illustrated and described, but may assume numerous other equivalent forms coming within the scope of the appended claims which define the limits of my invention.

I claim:

1. In a heater of the class described, the combination of a burner, a carburetor connected to the burner for supplying a combustible mixture thereto, a blower having a casing with a conduit which feeds air therefrom to the carburetor, said burner including means forming a combustion chamber and heat radiating means attached thereto, said blower casing being mounted closely adjacent the combustion chamber, and means forming an exhaust passage formed integrally within awall of the blower casing and connected with said combustion chamber for transferring heat from the exhaust gases to the air supplied by the blower to the carburetor.

2. In a heater of the class described, the combination of a burner, a carburetor connected to the burner for supplying a combustible mixture thereto, a-blower having a casing with a conduit which feeds air therefrom to the carburetor, said burner including means forming a combustion chamber 1 and heat radiating means attached thereto, means forming an exhaust passage having a restricted portion through which it is connected with said combustion chamber, and a conduit extending from the blower casing and discharging into the combustion chamber adjacent its connection with the exhaust passage a? d in a direction transverse to the axis of said restricted portion of the passage to supply air for diluting the exhaust gases.

3. In a heater of the class described, the combination of a'burner, a carburetor connected to the burner for supplying a combustible mixture thereto, a blower having a casing with a conduit which feeds air therefrom to the carburetor, said burner including means forming a combustion chamber and heat radiating means attached thereto, means forming an exhaust passage connected with said combustion chamber, and a conduit extending from the blower casing and discharging into the combustion chamber adjacent its connection with the exhaust passage and in a direction transverse to the axis of the exhaust passage at its said connection.

4. In a heater of the class described, the combinatiori of a burner, a carburetor connected to the burner for supplying a combustible mixture thereto, means for supplying air under pressure to said carburetor, said burner including means forming a combustion chamber and heat radiating means attached thereto, means forming an exhaust passage having a restricted portion through which it is connected with said combustion chamber, and means for feeding air under pressure to the combustion chamber adjacent its connection with the exhaust passage and in a bination of a burner, a carburetor connected to direction transverse to the axis of said restricted portion of the passage.

5. In a heater of the class described, the comthe burner for supplying a combustible mixture thereto, means for supplying air under pressure to said carburetor, said burner including means forming a combustion chamber and heat radiat-- ing means attached thereto, means forming an exhaust passage connected with said combustion chamber, and means for feeding air under pres-.

sure to the combustion chamber adjacent its connection with the exhaust passage and in a direc-v tion transverse to the axis of the exhaust passage at its said connection.

HENRY J. DE N. McCOLLUM.

nnr nanncns crrnn The following referencesare of record in the file of this patent:

UNITED s'ra'rns rsm'rs Number Name Date 1 2,225,112 I Hill Dec. 17, 1940 1,971,246 11 Anderson Aug. 21, 1934 1,658,198 InHosch Feb. 7, 1928 2,047,471 Hepburn et al. July 14, 1936 1,267,760 IV Good May 28, 1918 1,379,178 Good May 24, 1921 2,286,857 Holthouse June 16, 1942 2,105,626 Williams Jan. 18, 1938 2,286,853 Holthouse June 16, 1942 1,382,002 Leslie et a1. June 21, 1921 1,333,229 Toles Mar. 9, 1920 937,265 Philipski Oct. 19, 1909 2,296,185 Rose Sept. 15, 1942 1,733,792 Good Oct. 29, 1929 I 1,699,407 Reid Jan. 15', 1929 1,567,287 Morphy Dec. 29,-1925 

